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pagewalk: fix walk_page_range() don't check find_vma() result properly
[mirror_ubuntu-artful-kernel.git] / mm / pagewalk.c
CommitLineData
e6473092
MM
1#include <linux/mm.h>
2#include <linux/highmem.h>
3#include <linux/sched.h>
d33b9f45 4#include <linux/hugetlb.h>
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5
6static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
2165009b 7 struct mm_walk *walk)
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8{
9 pte_t *pte;
10 int err = 0;
11
12 pte = pte_offset_map(pmd, addr);
556637cd 13 for (;;) {
2165009b 14 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
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15 if (err)
16 break;
556637cd
JW
17 addr += PAGE_SIZE;
18 if (addr == end)
19 break;
20 pte++;
21 }
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22
23 pte_unmap(pte);
24 return err;
25}
26
27static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
2165009b 28 struct mm_walk *walk)
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29{
30 pmd_t *pmd;
31 unsigned long next;
32 int err = 0;
33
34 pmd = pmd_offset(pud, addr);
35 do {
03319327 36again:
e6473092 37 next = pmd_addr_end(addr, end);
03319327 38 if (pmd_none(*pmd)) {
e6473092 39 if (walk->pte_hole)
2165009b 40 err = walk->pte_hole(addr, next, walk);
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41 if (err)
42 break;
43 continue;
44 }
03319327
DH
45 /*
46 * This implies that each ->pmd_entry() handler
47 * needs to know about pmd_trans_huge() pmds
48 */
e6473092 49 if (walk->pmd_entry)
2165009b 50 err = walk->pmd_entry(pmd, addr, next, walk);
03319327
DH
51 if (err)
52 break;
53
54 /*
55 * Check this here so we only break down trans_huge
56 * pages when we _need_ to
57 */
58 if (!walk->pte_entry)
59 continue;
60
61 split_huge_page_pmd(walk->mm, pmd);
62 if (pmd_none_or_clear_bad(pmd))
63 goto again;
64 err = walk_pte_range(pmd, addr, next, walk);
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65 if (err)
66 break;
67 } while (pmd++, addr = next, addr != end);
68
69 return err;
70}
71
72static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
2165009b 73 struct mm_walk *walk)
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74{
75 pud_t *pud;
76 unsigned long next;
77 int err = 0;
78
79 pud = pud_offset(pgd, addr);
80 do {
81 next = pud_addr_end(addr, end);
82 if (pud_none_or_clear_bad(pud)) {
83 if (walk->pte_hole)
2165009b 84 err = walk->pte_hole(addr, next, walk);
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85 if (err)
86 break;
87 continue;
88 }
89 if (walk->pud_entry)
2165009b 90 err = walk->pud_entry(pud, addr, next, walk);
e6473092 91 if (!err && (walk->pmd_entry || walk->pte_entry))
2165009b 92 err = walk_pmd_range(pud, addr, next, walk);
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93 if (err)
94 break;
95 } while (pud++, addr = next, addr != end);
96
97 return err;
98}
99
116354d1
NH
100#ifdef CONFIG_HUGETLB_PAGE
101static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
102 unsigned long end)
103{
104 unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
105 return boundary < end ? boundary : end;
106}
107
108static int walk_hugetlb_range(struct vm_area_struct *vma,
109 unsigned long addr, unsigned long end,
110 struct mm_walk *walk)
111{
112 struct hstate *h = hstate_vma(vma);
113 unsigned long next;
114 unsigned long hmask = huge_page_mask(h);
115 pte_t *pte;
116 int err = 0;
117
118 do {
119 next = hugetlb_entry_end(h, addr, end);
120 pte = huge_pte_offset(walk->mm, addr & hmask);
121 if (pte && walk->hugetlb_entry)
122 err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
123 if (err)
124 return err;
125 } while (addr = next, addr != end);
126
127 return 0;
128}
129#endif
130
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131/**
132 * walk_page_range - walk a memory map's page tables with a callback
7682486b
RD
133 * @mm: memory map to walk
134 * @addr: starting address
135 * @end: ending address
136 * @walk: set of callbacks to invoke for each level of the tree
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137 *
138 * Recursively walk the page table for the memory area in a VMA,
139 * calling supplied callbacks. Callbacks are called in-order (first
140 * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
141 * etc.). If lower-level callbacks are omitted, walking depth is reduced.
142 *
2165009b
DH
143 * Each callback receives an entry pointer and the start and end of the
144 * associated range, and a copy of the original mm_walk for access to
145 * the ->private or ->mm fields.
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146 *
147 * No locks are taken, but the bottom level iterator will map PTE
148 * directories from highmem if necessary.
149 *
150 * If any callback returns a non-zero value, the walk is aborted and
151 * the return value is propagated back to the caller. Otherwise 0 is returned.
152 */
2165009b
DH
153int walk_page_range(unsigned long addr, unsigned long end,
154 struct mm_walk *walk)
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155{
156 pgd_t *pgd;
157 unsigned long next;
158 int err = 0;
159
160 if (addr >= end)
161 return err;
162
2165009b
DH
163 if (!walk->mm)
164 return -EINVAL;
165
166 pgd = pgd_offset(walk->mm, addr);
e6473092 167 do {
5f0af70a
DS
168 struct vm_area_struct *uninitialized_var(vma);
169
e6473092 170 next = pgd_addr_end(addr, end);
d33b9f45 171
5f0af70a 172#ifdef CONFIG_HUGETLB_PAGE
5dc37642
NH
173 /*
174 * handle hugetlb vma individually because pagetable walk for
175 * the hugetlb page is dependent on the architecture and
176 * we can't handled it in the same manner as non-huge pages.
177 */
d33b9f45 178 vma = find_vma(walk->mm, addr);
4b6ddbf7 179 if (vma && vma->vm_start <= addr && is_vm_hugetlb_page(vma)) {
d33b9f45
NH
180 if (vma->vm_end < next)
181 next = vma->vm_end;
116354d1
NH
182 /*
183 * Hugepage is very tightly coupled with vma, so
184 * walk through hugetlb entries within a given vma.
185 */
186 err = walk_hugetlb_range(vma, addr, next, walk);
5dc37642
NH
187 if (err)
188 break;
116354d1 189 pgd = pgd_offset(walk->mm, next);
d33b9f45
NH
190 continue;
191 }
5dc37642 192#endif
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193 if (pgd_none_or_clear_bad(pgd)) {
194 if (walk->pte_hole)
2165009b 195 err = walk->pte_hole(addr, next, walk);
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196 if (err)
197 break;
d33b9f45 198 pgd++;
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199 continue;
200 }
201 if (walk->pgd_entry)
2165009b 202 err = walk->pgd_entry(pgd, addr, next, walk);
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203 if (!err &&
204 (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
2165009b 205 err = walk_pud_range(pgd, addr, next, walk);
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206 if (err)
207 break;
d33b9f45
NH
208 pgd++;
209 } while (addr = next, addr != end);
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210
211 return err;
212}